                :placeholder "Kill Christián"
                :value (:filter (:topic @lepton))}])))
 
-(defn- topic-links []
-  (let [the-links (for [t (:filtered-topics (:topic @lepton))]
-                    [:li {:key (:id t)}
-                     [:a {:href (str "/entries/topic-add/" (:id t))} (:topic t)]])]
+(defn- show-topic-link [topic]
+  (letfn [(add-current-topic! []
+            (let [current-topics (:current (:topic @lepton))]
+              (swap! lepton assoc-in [:topic :current] (conj current-topics (:id topic)))))]
+    [:li {:key (:id topic)}
+     [:a {:href "#"
+          :on-click add-current-topic!} (:topic topic)]]))
+
+(defn- show-topic-links []
+  (let [the-links (for [t (:filtered-topics (:topic @lepton))] (show-topic-link t))]
     [:div#sidebar-wrapper
      [:ul.sidebar-nav
-      [:li.sidebar-brand (topic-filter)]
+      [:li.sidebar-brand (show-topic-filter)]
       the-links]]))
 
 (defn buttock-page []

       [:div#header
        [:img {:src "img/gretel.jpg"}]]
       [:div.content
        (page-links)
        (topic-links)
        [:div#entries
         "entries!"
         [:div [:a {:href "/"} "go home"]]]]])))

(def ^:private lepton (atom {:entry-count 40
                             :topic {:topics []
                                     :filter ""
                                     :filtered-topics []
                                     :current #{}}}))

;; ---------------------
;; logic
